Our long-term objective is to obtain a better understanding of the functional properties of glycosphingolipids in these recognition phenomena and to be able to identify and correct conditions in which defects in glycolipids are key elements in the mechanism of induction of disease. To this end, we plan to continue a multifaceted attack on this problem. First, we will isolate and characterize as many lymphocyte glycolipids as possible using newly developed, highly sensitive methods that include high-pressure liquid chromatography and mass spectrometry. Second, we will use monospecific antibodies (conventional and monoclonal) in immunohistochemical studies by using the fluorescence-activated cell sorter to define and isolate new subsets of lymphocytes in relationship to previously described functional subsets. For example, we will continue to examine the relationship between asialo GM1 and its sialated derivatives with natural killer function in mice using chemical, immunological, and enzymological techniques. We will apply this same approach to the analysis of spontaneous leukemias and lymphomas in mice and humans in attempts to define the role of GSL in growth control, and we will apply our knowledge of the chemistry of unique lymphocyte glycolipid antigens to assess their ability to interact with biologically active molecules in the lymphoreticular system, such as thymic hormones and lymphocyte growth factors. Recent work in this laboratory on the expression of glycolipids on the surface of mouse macrophages using the galactose oxidase/borotritide method indicates that induction of tumoricidal macrophages with BCG or gamma-interferon results in an alteration in the three-dimensional configuration of the cell surface. This can be seen by increased exposure of specific glycolipids on the surface of tumoricidal macrophages, probably due to domain formation. It is thus apparent that the analysis of the conformation of macromolecules on the surface of some effector cells in the immune system may be as important as the mere presence or absence of specific surface markers. (CS)